Lithium niobate (LN) microdisk resonators on a LN-silica-LN chip were fabricated using only conventional semiconductor fabrication processes. The quality factor of the LN resonator with a 39.6-μm radius and a 0.5-μm thickness is up to 1.19 × 10(6), which doubles the record of the quality factor 4.84 × 10(5) of LN resonators produced by microfabrication methods allowing batch production. Electro-optic modulation with an effective resonance-frequency tuning rate of 3.0 GHz/V was demonstrated in the fabricated LN microdisk resonator.

The application of three-dimensional (3D) plasmonic nanostructures as metamaterials (MMs), nano-antennas, and other devices faces challenges in producing metallic nanostructures with easily definable orientations, sophisticated shapes, and smooth surfaces that are operational in the optical regime and beyond. Here, we demonstrate that complex 3D nanostructures can be readily achieved with focused-ion-beam irradiation-induced folding and examine the optical characteristics of plasmonic ''nanograter'' structures that are composed of free-standing Au films. These 3D nanostructures exhibit interesting 3D hybridization in current flows and exhibit unusual and well-scalable Fano resonances at wavelengths ranging from 1.6 to 6.4 mm. Upon the introduction of liquids of various refractive indices to the structures, a strong dependence of the Fano resonance is observed, with spectral sensitivities of 1400 nm and 2040 nm per refractive index unit under figures of merit of 35.0 and 12.5, respectively, for low-order and high-order resonance in the near-infrared region. This work indicates the exciting, increasing relevance of similarly constructed 3D free-standing nanostructures in the research and development of photonics and MMs.